There is a need to have a portable tool capable of generating high forces to drive fasteners such as a 31/2 inch long nail. The current prevalent tool for driving such fasteners requires a continuous source of pressurized air. There have been attempts at developing portable tools using internal combustion principles such as those illustrated in Liesse U.S. Pat. Nos. 3,042,008 and 4,200,213 and Smith U.S. Pat. No. 3,967,771. In addition to those patents it is to be noted that the assignee of the present invention has made a significant development in this area as covered by two pending patent applications filed Jan. 22, 1981 in the name of M. Nikolich entitled "Combustion Gas Powered Fastener Driving Tool", Ser. No. 227,194 now U.S. Pat. No. 4,403,722 and "Portable Gas-Powered Tool With Linear Motor", Ser. No. 227,193 both of which are assigned to the assignee of the present invention. The tools shown in these applications will be referred to herein since a number of the features covered in the instant application are improvements over such tools.
It is to be noted that some of the basic concepts employed in the tools illustrated in the aforementioned Nikolich applications are incorporated in the tools illustrated herein. While sufficient details will be set forth herein for an understanding of the present invention, if further information is desired reference may be made to such applications which are incorporated herein by reference. It is to be noted that the tools disclosed in the aforementioned Nikolich applications are believed to be totally satisfactory and that as in all such developments improvements are continuously being made to increase the efficiency and operability of such tools and it is in these areas that the instant application is directed.